It should have been out two years ago so presumably they have had a team of engineers for all this time trying to tweak it to an acceptably high standard.

That is acceptable standard for $10k ... no doubt the prototypes that were talked about were great as they were, but obviously Canon doesn't want to release a mk2 in 2015 and is determined to make this one special as in "especially profitable" - and this only works if lots of people buy it so it has to be stellar.